Other glaciers can only be saved if greenhouse gas emissions are “drasically reduced” and global warming is limited to 1.5 degrees Celsius, Paris-based UNESCO warned in its report.
The world’s melting glaciers are giving up their secrets too soon
About 50 of the organization’s more than 1,150 World Heritage Sites have glaciers, which together make up nearly one-tenth of the world’s glacial area.
The nearly 19,000 glaciers in heritage sites lose more than 60 billion tons of ice each year, which is the annual water consumption of Spain and France combined, and accounts for about 5 percent of global sea level rise, according to UNESCO.
“Glaciers are retreating at an accelerated pace worldwide,” said Tales Carvalho Resende, a hydrology expert at UNESCO.
The organization described a “warming cycle” in which the melting of glaciers causes the emergence of dark surfaces, which then absorb even more heat and accelerate the retreat of ice.
In addition to drastic reductions in emissions, the UNESCO report calls for better monitoring of glaciers and the use of early warning mechanisms to respond to natural disasters, including flooding caused by bursting glacial lakes. Such floods have already claimed thousands of lives and may have partially fueled Pakistan’s catastrophic flooding this year.
While there have been some local attempts to slow the melt rate — for example, by covering the ice with blankets — Carvalho Resende warned that scaling up those experiments “could be extremely challenging because of the cost, but also because most glaciers are very difficult to access.” .”
Throughout history, glaciers have grown during very cold spells and shrunk when those stretches ended. The world’s last very cold spell ended more than 10,000 years ago, and more natural melting was expected in Europe after the last “Little Ice Age” ended in the 19th century.
But as carbon dioxide emissions increased over the past century, human factors began to accelerate what was expected to be a gradual natural retreat. In Switzerland, glaciers lost a record 6 percent of their volume this year.
While the additional melting has to some extent offset other effects of climate change — for example, by preventing rivers from drying out despite heat waves — it is quickly reaching a critical threshold, according to UNESCO.
In its report, the organization writes that the meltwater peak may have already passed on much smaller glaciers, where the water is now beginning to recede.
If the trend continues, the organization warned, “little to no base power will be available during the drier periods.”
The changes are expected to have a major impact on agriculture, biodiversity and urban life. “Glaciers are critical sources of life on Earth,” UNESCO wrote.
“They provide water to at least half of humanity,” said Carvalho Resende, who warned the cultural losses would also be huge.
Around the world, global warming is exposing ancient artifacts faster than archaeologists can save them.
“Some of these glaciers are sacred sites, which are very important to indigenous peoples and local communities,” he said.
UNESCO cited the example of the ancient Snow Star Festival in the Peruvian Andes, which has already been affected by ice loss. Spiritual leaders once shared blocks of glacial ice with pilgrims, but the practice was discontinued when locals noticed the rapid retreat in recent years.
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Small glaciers at low or medium elevations will be the first to disappear. UNESCO said ice loss rates in small glacial areas “more than doubled from the early 2000s to the late 2010s.”
This is consistent with observations made by researchers who have studied glacier retreat. Matthias Huss, a European glaciologist, said scientists had seen “a very strong melt” in Switzerland over the past two decades.
At the same time, there are fewer and fewer places where it is cold enough for glaciers to actually grow. “Today, the limit where glaciers can still form new ice is about 3,000 meters [about 9,840 feet]’ he said, explaining that that height has risen several hundred meters in recent decades.